1. Field of the Invention
The present invention relates to a solid state image device and its defective pixel recording method which is applied to CCD camera arranging a solid state image element in a matrix shape and in a high density and is preferable. More particularly, the present invention is characterized in that position selection means for selecting a position of defective pixel on the screen is provided, this position selection means is manually operated and positional information of selected defective pixel is recorded in the memory means, if a new defective pixel is occurred in a solid state image element after shipping the product, without using any special jig for writing, in addition, positional information which is difficult to deal with by the automated writing mode has been made easily additionally written.
2. Description of the Related Art
Recently, there have been many cases where a video camera is used in which a solid state image element (CCD) is arranged in a high density and in a matrix shape. In this kind of video camera, pixels which are not normally operated in a certain rate (hereinafter, as referred to defective pixel) are generated and appeared as dotted fixed noises (so called white and bright defect: white defect) on the screen. It is considered that this was occurred because pn junction of light electronic conversion element is destroyed or somehow done by intervention of cosmic rays and radiation on the way of traveling after shipping the product or at the place where the camera is set. Therefore, there have been many cases where defective correction system for removing its influence by adjusting white defect is mounted in CCD camera.
According to the defective correction system 10 of the CCD camera 1 shown in FIG. 1, a defective pixel recording method using one time ROM is employed, and an image acquisition information related to defective pixel is adjusted by memorizing the adjusted data into ROM2. As for white defect which is occurred posteriorly, after existing ROM2 is removed from the CCD camera in step B1 of flowchart shown in FIG. 2, a new ROM2 is set in the writing jig 3. Then, in step B3, the position of defective pixel is measured, and after that, in step B4, a corrected data to an image acquisition information related to defective pixel is prepared, this is written into a new ROM2, and then, in step B5, the ROM2 is removed from the writing jig 3 and mounted so as to exchange with the old ROM2 set in the CCD camera 1.
Now, according to the defective correction system 10 using one time ROM, since it needs the writing jig 3 which is exclusive such as ROM writer and the like, burden is heavy from the point of view of facilities. Then, a method of mounting a non-volatile memory in the CCD camera, detecting a position related to defective pixel by scanning on the screen with camera itself, and employing automatic writing mode in which the correction data prepared based on its positional information is written into a memory is designed.
However, white defect, which can be dealt with by automatic writing mode, may remain. For example, there is a problem that it is difficult to selectively correct white defect as repeating flickering periodically, and white defect and the like which cannot be deleted because of the limitation of defective correction system.
It should be noted that the limitation of defective correction system is occurred in a case where correction number related to defective pixel on the identical line is defined, refers to a fact that defective pixel exceeding over its correction number of pieces cannot be recorded. Moreover, white defect which could not be deleted due to the limitation of the defective correction system refers to a portion which is white and bright due to defective pixels exceeding over the correction number of pieces on the same line.